Question

using a 60-MHz spectrometer, a chemist observes the follow resonance. doublet, J=7 Hz at δ 4.00. What would the chemical shift ( δ ) be in the 300-MHz spectrum?

Answer 1

The chemical shift observed at δ 4.00 using a 60-MHz spectrometer would also be δ 4.00 in a 300-MHz spectrum because chemical shifts are reported in ppm, which is frequency-independent.

Step-by-step explanation:

The question pertains to how the chemical shift of a resonance peak in a 1H-NMR spectrum changes when measured using different frequencies of NMR spectrometers.

The chemical shift is reported in parts per million (ppm) and remains constant across different spectrometer frequencies. Therefore, if a chemist observes a resonance doublet with a J-coupling constant of 7 Hz at δ 4.00 using a 60-MHz spectrometer, the same doublet would appear at the same chemical shift (δ 4.00) in a 300-MHz spectrum, because ppm is a unit that is independent of the spectrometer’s operating frequency.